1. Field of the Invention
The present invention refers to a shutter action finish signal generating device, particularly for a camera designed that the shutter is opened and closed by the to and fro motion or the shutter blade driving member.
2. Description of the Prior Art
Generally, it is necessary to transfer the finish signal of the shutter opening and closing action to the camera side by some means. The reason is that it is necessary to start the current supply to the camera winding motor, to initiate automatic film winding after the shutter opening and closing action, to automatically wind the film, or if necessary, to unlock the winding safety device so as to enable manual winding. Further, the shutter action finish signal, namely, the shutter close signal, is also used at the same time to unlock the press permit mechanism of the release button so as to make the release operation possible again.
In the case of the conventional shutter device so designed that the shutter is opened and closed by rotating the shutter driving member along one direction by means of a tensioned spring, such a shutter close signal can easily be obtained. However, in the case of the shutter device so designed that the shutter is opened and closed by means of the to and fro motion of the shutter blade or the shutter driving member, the shutter blade or its driving member assumes the same phase before the shutter opening and after the shutter closing. In other words, the position of the shutter blade is the same before its opening and after its closing, so that it is difficult to provide a shutter close signal.
Particularly in case of the electromagnetically driven shutter so designed that the shutter blade is electromagnetically moved to and fro, a sufficiently large electromagnetic force for driving the shutter blade cannot be obtained due to various restrictions, so that it is impossible to form the shutter close signal by means of the shutter blade or its driving member and, therefore, it is difficult, in practice, to construct a camera with such a shutter device.